Shift lever vibration isolation assembly and methods of manufacture

ABSTRACT

A shift lever assembly designed to isolate vibrations including an outer can having a bore and an outer wall, an inner can disposed within the bore, a vibration absorbing material positioned within the bore and around the inner can; and a sleeve extending from the outer wall of the outer can. The method of making the shift lever assembly includes positioning an outer can having a bore and an attached sleeve in a mold, positioning an inner can in the mold, within the bore of the outer can, injecting a vibration absorbing material into the mold, thereby filling the space within the bore of the outer can around the inner can, and allowing the vibration absorbing material to cure, thereby securing the inner can within the outer can.

This application is a continuation of U.S. patent application Ser. No.12/006,913, filed Jan. 7, 2008, and claims priority of U.S. provisionalApplication No. 60/879,258 filed Jan. 8, 2007, which is incorporatedherein by reference.

TECHNICAL FIELD

In general, the present invention relates to a shift lever vibrationisolation assembly. In particular, the present invention relates to ashift lever vibration isolation assembly having an outer can that housesan inner can surrounded by vibration-absorbing material, and a sleeveattached to the outer can for receiving a shift lever. The presentinvention also relates to a method of manufacturing the shift levervibration isolation assembly.

BACKGROUND ART

Shift lever assemblies which absorb or isolate vibrations are known topersons skilled in the art. Such assemblies can be used in manyapplications to isolate or absorb vibration sources. Typical of suchapplications would be the transmission shift lever in a vehicle.Existing shift lever vibration isolation assemblies, as depicted in FIG.1, typically include an outer can A having an inner can B receivedtherein, with vibration-absorbing material C located between the innerand outer can. The outer can has a shift lever D emanating from theoutside wall of the outer can, with the shift lever being welded to theoutside wall of the outer can. The shift lever is welded to the canbefore the vibration-absorbing material is provided within the canbecause heat transfer from the welding process would destroy the bondbetween the vibration-absorbing material and the can. The heat transferfrom the welding process would also destroy the vibration-absorbingmaterial, which is typically an elastomer, as it is immediately adjacentto the welding heat without a heat sink.

Alternative production methods which might otherwise produce a betterproduct have thus far proven impractical due to time and costsconstraints. Particularly, due to the large size of the shift lever, itis not practical to use an molding process to form the vibrationabsorbing material within the outer can after the shift lever has beenwelded to the outer can. The size of the shift lever severely limits thenumber of assemblies that can be molded at one time, making the processextremely inefficient and cost prohibitive. As a result of the weldingrequired to attach the shift lever to the outer can and the necessity todo so prior to insertion of the rubber insert which absorbs vibrations,conventional shift lever assemblies have used rubber cement to attachthe rubber insert. The rubber cement does not provide an ideal bondbetween the rubber insert and the outer and inner cans. The presentinvention improves upon this by allowing rubber to be injected directlyinto an outer can supported in a mold, as will be described morecompletely below.

DISCLOSURE OF THE INVENTION

It is thus an object of the present invention to provide a shift levervibration isolation assembly adapted to allow a shift lever to besecured thereto with or without welding.

It is a further object of the present invention to provide a shift levervibration isolation assembly having an improved bond between the outerand inner can and the elastomer.

It is an additional object of the present invention to provide a shiftlever vibration isolation assembly having an outer can with a sleeveextending therefrom.

It is another object of the present invention to provide a moreefficient and cost effective method of manufacturing a shift levervibration isolation assembly.

These and other objects of the present invention, as well as theadvantages thereof over existing prior art forms, which will becomeapparent from the description to follow, are accomplished by theimprovements hereinafter described and claimed.

A preferred exemplary shift lever vibration isolation assembly includesan outer can having a bore, an inner can disposed within the bore, avibration absorbing material positioned within the bore and around theinner can, and a sleeve attached to the outer wall of the outer can.

A preferred exemplary method of producing the shift lever vibrationisolation assembly of the present invention includes positioning anouter can having a bore and a sleeve in a mold, positioning an inner canin the mold, within the bore of the outer can and spaced from the outercan, injecting a vibration absorbing material into the mold, therebyfilling the space within the bore of the outer can around the inner can,and allowing the vibration absorbing material to cure, thereby securingthe inner can within the outer can.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a prior art design of a shift levervibration isolation assembly;

FIG. 2 is an perspective view of the shift lever vibration isolationassembly according to the concepts of the present invention;

FIG. 3 is a sectional view of the shift lever assembly takensubstantially along line 3-3 of FIG. 2;

FIG. 4 is an perspective view of an inner can having a positive stopaccording to the concepts of the present invention; and

FIG. 5 is a sectional view, similar to FIG. 3, of a second embodiment ofthe shift lever assembly of the present invention in which the outer canincludes a top edge that is rolled over.

PREFERRED EMBODIMENT FOR CARRYING OUT THE INVENTION

In general, the present invention includes a vibration isolationassembly indicated by the number 10 in the accompanying drawings. Thevibration isolation assembly 10 is generally used to attenuate or absorbvibrations from a source object before the vibrations reach a user. Thevibration isolation assembly described herein may be used in a number ofapplications. For the sake of simplicity, the following descriptionrelates to a shift lever vibration isolation assembly. This assembly isshown and described as one example of the present invention and shouldnot be considered limiting. With reference to FIGS. 2 and 3, vibrationisolation assembly 10 generally includes an outer can 12 having an outerwall 13, an inner can 14 housed within the outer can 12, andvibration-absorbing or isolating material 16 located between the outerand inner cans 12, 14. In accordance with the concepts of the presentinvention, a sleeve 18 is attached to the outer can 12 to which a shiftlever or other object (not shown) may be attached.

It will be appreciated that outer can 12 may have any shape thatsuitably receives inner can 14 and vibration-absorbing material 16. Theouter can 12 includes a bore 19 in all embodiments, regardless of itsshape, to allow inner can 14 and vibration-absorbing material 16 to bedisposed therein. Bore 19 is defined by the inner wall 20 of outer can12. The outer can 12 may be taller, shorter, or otherwise dimensionedaccording to the particular application where it will be used. The sameholds true for inner can 14 and sleeve 18. These may have any shape ordimension depending upon a particular application. In general, outer can12 acts as an adapter for attaching an object, such as a shift lever forexample, to another object, such as a transmission, where vibration isemanating or terminating. The shapes of the outer can 12, the inner can14, and the sleeve 18 are not to be considered limiting.

Also, while the sleeve 18 is shown as attached to outer wall 13 of outercan 12, it will be appreciated that these components may be formed asone piece, for example, as by casting or extrusion. For sake ofsimplicity, the term “attached” will be used in its traditional senseand also to include the formation of separate parts as a single piece.In addition, sleeve 18 may be of any shape or construction so long as ashift lever or other object may be attached thereto. For instance,sleeve 18 may also be of a piece of bar stock, or a half cylinder, towhich an object may be attached.

By using sleeve 18, objects of any shape or size may be later affixed tovibration-isolation assembly 10 in any method known in the artincluding, for example, press fitting, weldment, swaging, or through theuse of adhesives or traditional fasteners. Beneficially, the shift leveror other object may be attached to sleeve 18 after vibration-absorbingmaterial 16 is provided into outer can 12. By adding the sleeve 18, whenattaching the shift lever, in contrast to the prior-art method ofdirectly attaching the shift lever to outer can 12, it is possible toheat sink the outer can 12 protecting elastomeric vibration-absorbingmaterial 16 and the bond formed between the material 16 and the outercan 12. In some cases, this may eliminate the need for the use ofadhesives to join vibration-absorbing material 16 to outer can 12. Asshown, sleeve 18 is made smaller than the object being attached to outercan 12 to increase the number of assemblies 10 that can be processed ina single mold. Sleeve 18 may, however, be of any suitable size and shapefor mounting an object to the assembly. FIG. 1 shows a prior-art can andshift lever combination for purposes of comparison. In the example shownin FIGS. 2 and 3, sleeve 18 is shorter than outer can 12.

As best shown in FIG. 3, inner can 14 may be made hollow to act as areceiver for attaching the vibration-isolation assembly 10 to a secondobject, such as a transmission in a vehicle. In this application, innercan 14 may be provided with stops 22, 24 that extend outwardly frominner can 14 in a radial direction. The stops 22, 24 create areas wherea relatively small amount of absorbing material 16 separates the outercan 12 from inner can 14. This results in improved feedback to theoperator and a system that is more responsive to the inputs from theoperator by creating near metal-to-metal contact between inner wall 20of outer can 12 and inner can 14 when the shift lever is moved. It willbe appreciated that the stops 22, 24 may have virtually any shape andmay be patterned to facilitate manufacturing or improve function. Forexample, stops 22, 24 may be provided with scalloped inside or outsidediameters or with through holes to assist the flow of elastomer andallow the escape of trapped gases during molding of the absorbingmaterial 16 around inner can 14. Stops 22, 24 may also be shaped to haveprojecting portions that may be oriented so that stops 22, 24 reduce theamount of material between the outer can and the inner can in selecteddirections. The shapes of the stops 22, 24 should not be considered aslimiting the scope of the present invention. It will be appreciated thatstops 22, 24 may alternatively be attached to the inner wall 20 of outercan 12 and operate in the same fashion.

Stops 22, 24 as shown in FIG. 3 may be attached in any manner to eitherinner can 14 or outer can 12, including by being seamlessly bonded, bywelding, by press fitting, or by one-piece formation. The means ofattaching stops 22, 24 to inner can 14 or outer can 12 should not beviewed as limiting the scope of the present invention. Advantageously,the attachment of stops 22, 24 allows them to be placed inwardly of theextreme outer ends of outer can 12. Existing designs suggest placingpositive stops at the extreme outer ends of the can without anyattachment. In these designs, in addition to the undesirable formationof elastomeric flash, the elastomeric material often seeps between theinner can 14 and stops 22, 24, requiring additional machining to clearthis material. FIG. 4 depicts an alternate embodiment of the attachmentof stop 24 to inner can 14 in which stop 24 is tack welded to inner can14. Stop 24 has an inner diameter that is slightly larger than the outerdiameter of inner can 14, thereby creating a gap 26 therebetween. Tackwelds 28 acts to hold stop 24 in place during the molding process, whileallowing the elastomer, as well as air and gas, to flow through the gap26 between inner can 14 and stop 24.

To form the vibration-absorbing material 16 between the inner can 14 andouter can 12, the outer can 12 with sleeve 18 attached may be providedin a mold with the inner can 14 supported within the bore of outer can12 and spaced from the inner wall 20 of outer can 12. As will beappreciated, due to the shorter height of the outer can 12 and sleeve 18combination relative to existing can and shift lever combinations, alarge number of outer can 12 and inner can 14 assemblies may be locatedin a single mold. With the outer can 12 and inner can 14 arranged in amold, elastomeric material or other suitable vibration-absorbingmaterial is injected into the mold to fill the voids between outer can12 and inner can 14. The elastomer 16 may be chemically attached toouter can 12 and inner can 14 or secured by mechanical entrapment. Forexample, the end 30 of outer can 12 may be rolled over as depicted inFIG. 5 to entrap vibration-absorbing material 16. Advantageously, thiseliminates the additional step of applying adhesives or chemicallybonding the elastomeric material to outer can 12.

What is claimed is:
 1. A method of producing a shift lever assemblycomprising the steps of: positioning an outer can having a bore and asleeve in a mold; positioning an inner can in the mold, within the boreof the outer can and spaced from the outer can; injecting a vibrationabsorbing material into the mold, thereby filling the space within thebore of the outer can around the inner can; and allowing the vibrationabsorbing material to cure, thereby securing the inner can within theouter can.
 2. The method of claim 1 further comprising the step ofproviding at least one stop between the inner can and the outer canbefore injecting a vibration absorbing material into the mold.
 3. Themethod of claim 2 further comprising the step of providing a gap betweenthe at least one stop between the inner can and the outer can andallowing the vibration absorbing material to flow through the gap wheninjected into the mold.
 4. The method of claim 2 further comprising thestep of press fitting the at least one stop between the inner can andthe outer can.
 5. The method of claim 2 further comprising the step ofwelding the at least one stop to the inner can before positioning theinner can in the bore of the outer can.
 6. The method of claim 2 furthercomprising the step of welding the at least one stop to the outer canbefore positioning the inner can in the bore of the outer can.
 7. Themethod of claim 1 wherein the inner can is positioned within the bore ofthe outer can so that at least one end of the inner can is not alignedwith an end of the outer can.
 8. The method of claim 1 furthercomprising the step of forming a chemical bond between the vibrationabsorbing material and the inner can and the outer can.
 9. The method ofclaim 1 further comprising the step of mechanical entrapment of theinner can within the bore of the outer can by the vibration absorbingmaterial.
 10. The method of claim 1 further comprising the step ofpositioning multiple outer cans each having a bore and a sleeve in amold; positioning an inner can in each of the outer can bores, andinjecting a vibration absorbing material into the mold, thereby fillingthe spaces within the bore of each of the outer cans around therespective inner cans; and allowing the vibration absorbing material tocure, thereby securing each of the inner cans within the respectiveouter cans.
 11. The method of claim 1 further comprising the stepcontaining the vibration absorbing material substantially within theouter can by the mold.
 12. The method of claim 1 further comprising thestep of shaping the at least one stop to allow flow of the vibrationabsorbing material between the inner can and the outer can.
 13. Themethod of claim 2 further comprising the step of providing two stopsbetween the inner can and the outer can, with a first stop positionedproximate to a first end of the inner can and a second stop positionedproximate to a second end of the inner can.
 14. The method of claim 2further comprising the step of locating the at least one stop inwardlyof an end of the outer can.
 15. The method of claim 2 further comprisingthe step of forming the at least one stop and the inner can as onepiece.
 16. The method of claim 2 further comprising the step of formingthe at least one stop and the outer can as one piece.
 17. The method ofclaim 1 further comprising the step of forming the outer can with atleast one end which is rolled over to entrap the vibration absorbingmaterial.
 18. The method of claim 1 further comprising the step ofapplying adhesive to the inner can prior to positioning the inner can inthe mold within the bore of the outer can.
 19. The method of claim 1further comprising the step of applying adhesive to the outer can priorto positioning the outer can in the mold and prior to positioning theinner can within the bore of the outer can.
 20. A method ofmanufacturing a shift lever vibration isolation assembly, comprising thesteps of: providing an outer can having a bore and an outer surface;attaching a sleeve to the outer surface of the outer can; providing amold having at least one mold cavity for receiving the outer can andsleeve attached to the outer surface of the outer can; positioning theouter can and sleeve attached to the outer surface of the outer can inthe mold; positioning an inner can within the bore of the outer can andspaced from an inner surface of the outer can, and introducing avibration absorbing material into the mold cavity and between the innercan and the inner surface of the outer can.
 21. The method of claim 20further comprising the step of providing at least one step between theinner can and the outer can before introducing the vibration absorbingmaterial into the mold cavity and between the inner can and the innersurface of the outer can.